Building Athens Without the Slaves

Self-reproducing machines could expand human horizons,
dramatically increase productivity, and cause an explosion of wealth before the
end of this century.

The heart is a pump, the eyes tiny cameras, the brain a computer: The human
body is a machine. Yet when Descartes first expressed this idea over 300 years
ago to his royal student, Queen Christina of Sweden, she came up with a cogent
question. "How," she asked, "can machines reproduce themselves?"

Until recently Queen Christina's question had no answer. A lathe can make
many useful things, but it can't duplicate its parts and put them together to
make a baby lathe identical to itself. To do so would require deep knowledge of
its own construction-the lathe would have to know itself. No machine ever has,
but recently engineers and scientists at NASA have shown that a self-replicating
machine could be built. With a relatively modest investment, a self-replicating
factory could be built by early next century. The Japanese have reached a
similar conclusion.

Self-replicating machines would be more than high-tech pets. Since they would
produce factories as well as products, self-replicating machines would be the
ultimate tools for increasing productivity. One application investigated by
the NASA group was to use a self-reproducing machine on the surface of the moon
to make solar cells, which could be cheaply hauled to vast solar-power satellites
that would beam solar energy back to earth. The researchers considered the task
of making one million solar cells out of the moon dust. A $1 billion, 100-ton
conventional factory would take about 6,000 years to perform this task. A self-replicating
factory of the same initial size and cost could do the job in just 20 years,
because it makes not only Solar cells but more solar-cell factories. Marvin
Minsky, artificial- intelligence expert at the Massachusetts Institute of Technology
and former president of the American Association for Artificial Intelligence,
recently wrote, "Teaching computers how to build copies of themselves could
begin a flood of automatic self-replication machines making more machines at
very low cost. Then we'll have to learn to cope with the resulting explosive
growth of wealth and productivity."

It was not until 1948 that scientists became convinced that machines could be
taught to replicate themselves. In that year John von Neumann, the
Hungarian-American mathematician who helped design the first stored-program
computer, gave a series of historic lectures at the University of Illinois. He
showed that to duplicate itself, a device must have available its own blueprint,
some manipulators-hands, essentially-and a set of rules for building things. The
beauty of von Neumann's approach was that he was able to prove, with
mathematical rigor, the possibility of building self-reproducing machines.

The simplest self-reproducing machine von Neumann imagined would sit in a
giant stockroom filled with replacement parts-extra arms, legs, eyes, circuit
boards, and the other paraphernalia from which it was built. The machine would
have a memory tape containing all the instructions needed to build a copy of
itself from these spare parts. Using its robot arm and its ability to move
around, the machine would find and connect parts. The tape program would
instruct the device to reach out and pick up a part, look to see if it's the
right one, and if not, put. it back and grab another. Eventually the correct one
would be found, then the next, and the two joined in accordance with the master
checklist. The machine would continue to follow the instructions, never knowing
what it is making, until it Finishes assembling a physical duplicate of itself.
But the new robot would be "uneducated"; it would have no instructions on its
tape. The parent would then copy its own memory tape onto the blank tape of its
offspring. The last instruction of the parent's tape would be to activate its
progeny.

Skeptics may scoff at this as mere instruction-book-style assembly. The parts
in the warehouse already were "almost" robots. Somebody had to build them ahead
of time. But some prefabrication of starting parts must be allowed. "After all,"
writes Dr. W. Ross Ashby, expert in biophysics at the Burden Neurological
Institute in England, "living things that reproduce do not start out as a
gaseous mixture of raw elements." Proteins, carbohydrates, and fats are the
sophisticated, prefabricated materials from which humans build copies of
themselves.

Some simple examples of machines that reproduce without human intervention
do exist. Small mechanical contrivances capable of self-assembly from simpler
parts are easy to build. Many years ago Roger Penrose, a British physicist,
fabricated a set of simple blocks that could hook together using a set of ratchets
and levers. When single parts are placed in a box-a track shaped like a long
trough-and shaken, they do not join together. However, when an interlocked,
two-block unit is placed in the box and shaken, a simple form of reproduction
takes place. Collisions between the two-block unit and other parts in the box
cause new two-block units to form, each identical to the original. Penrose successfully
tested replicating units of up to four blocks, using several different block
types.

Compact, self-replicating robots, capable of doing more than dumbly
duplicating, are far more difficult to build. Minsky says, "Today it might be
possible to build a self-replicating machine, but it might have to be the size
of a factory." Minsky believes that in the future these machines could be as
small as animals-also self-reproducing units. Charles Rosen, founder of the
Robotics and Automation Division of Stanford Research Institute and chief
scientist of the Machine Intelligence Corporation, agrees. "It is important to
recognize that a complex robot is not essential to make a useful machine. It is
possible to design a modular growing robot system, like the early lathes that
could produce parts that could make better lathes, which could then produce
parts that made better lathes, and so on. But the exercise has not been done. It
is an exciting concept that has yet to be fully explored, although I have little
doubt that it will be."

John van Neumann, mathematical father of self-reproducing
machines

A primitive self-reproducing robotable to assemble copies of itself from a parts
bincould be running within five
years.

The Japanese are already investigating the possibility of self-reproducing
machines. Ten years ago the Japanese Ministry of International Trade and
Industry began a feasibility study called "Methodology for Unmanned
Manufacturing." In 1977 the ministry plunked down $60 million in seed money for
a seven-year research and development program aimed at "complete automatic
manufacturing" by the start of the next century. The first prototype "unmanned"
production line was started two years ago by Fujitsu FANUC, a leading
international manufacturer of machinery. At the $40 million factory,
computer-controlled industrial robots build other industrial robots with minimum
human intervention. Only 100 human supervisory and manufacturing personnel are
needed, just one-tenth the usual number. An automated plant where robots make
robots is an important first step toward practical self-replicating systems.

A recent NASA study, conducted at the University
of Santa Clara in 1980 with the support of Ames Research Center and the American
Society for Engineering Education, examined the automation technologies needed
to achieve machine self-replication. These requirements were compared to the
existing state of the art in robotics and computer science. The surprising conclusion:
According to industry experts and the NASA analysis, a primitive self-reproducing
robot able to assemble copies of itself from a couple of dozen components drawn
from a parts bin could be running within five years, for a total investment
of from $5 million to $50 million using a specialist staff of only about a dozen
engineers.

The NASA study proposes to tackle the practical difficulties of machine
replication in a four-phase program. The first phase is just von Neumann's
simple robot in a warehouse. But by the fourth phase the NASA scientists hope to
have an entire, self-sufficient factory capable of building copies of itself
from raw material-natural ores and soils. This final "parent" replicating system
would be about the size of a football field, weigh 100 tons, and consume a few
megawatts of power, and it could reproduce itself about once a year.

When a linked pair of Penrose blocks
are placed in a trough with other blocks and shaken, copies form anywhere along
the track where an A piece happens to be immediately an the left of a B piece.

Ultimately, replicating machines could beturned loose to build giant manufacturing complexes on
themoon or to rework the surfaces of entire
planets.

Former NASA administrator Robert A. Frosch clearly understood the power of
self-reproducing factories. "It appears we can use machines in a
pseudo-biological way to establish a productive machine economy," he observed
during a 1979 speech on the future of robotics in NASA. "The key is the
construction of a machine which automatically, or with minimal human
[remote-control] guidance, can use solar energy and local materials on the earth
or elsewhere in the solar system to build a replica of itself. Then these
machines will construct further generations of machines."

Replicating systems are best employed when massive output is desired at
little cost or in hostile or inaccessible locations. A "seed" factory is
planted, which builds additional facilities so that it can produce useful
products. Possible products include large solar-cell arrays for electrical power
plants in the southwestern United States, desert irrigation and
soil-conditioning equipment covering vast areas, mass-production of automated
agricultural machines or military material, fleets of ocean-bottom mineral- and
metals-retrieving robots patrolling the continental shelves, and expansive
fields; of solar-power satellite groundr-receiver elements.

Replicating factories on the moon could make space exploration affordable.
"On the lunar surface we could build thousands of lunar rovers to cover the
moon like ants, measuring, exploring and mapping, surveying the entire surface
in just a few years," says Georg von Tiesenhausen, assistant director of the
Advanced Systems Office at the Marshall Space Flight Center in Huntsville, Alabama.
"By conventional methods this exploration might take a century or more." Ultimately,
replicating machines could be turned loose in space to build giant manufacturing
complexes on the moon, automatically assemble orbital space colonies, rework
the surfaces of entire planets such as Mars to make them fit for human habitation,
or make millions of automatic probes to be sent to other stars in search of
extraterrestrial intelligence.

Pessimists, such as, von Tiesenhausen, believe that within 20 years after the
project is begun, the United States could produce the first robot factory able
to replicate itself from raw materials. Frosch is more optimistic. "We are very
close to understanding how to build such machines," he says. "I believe that the
technology is presently available and that the necessary development could be
accomplished in a decade or so."

An early workshop sponsored by Gerard K. O'Neill, president of the Space Studies
Institute in Princeton, New Jersey, and an advocate of space colonies as the
future home of humankind, found that self-reproducing machines could dramatically
reduce the cost of the industrialization of space. Instead of the initial cost
estimates in the hundreds of billions of dollars, O'Neill found that self-replicating
systems "appear capable of achieving high levels of productivity for investments
considerably less than $10 billion. They would be in the range of the Alaska
pipeline ($7 billion), and much lower than the Churchill Falls, Quebec, electric
power system, both of which were private ventures." According to the NASA study,
the proposed self-replicating factory could repay its own initial start-up costs
after only a few years on the job. Comments British Agriculture Minister Peter
Walker: "Uniquely in history, we have the circumstances in which we can create
Athens without the slaves."

An artist's conception of NASA's factory that could make solar cells and
copies of itself out of moon dust early next century

Robert A. Freitas Jr. served on the Replicating
Systems Concept Team during the 1980 NASA study on space robotics.